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IECC R403 — Mechanical/Lighting/Water Systems (Residential)

Updated Mar 25, 2026

HVAC duct insulation/sealing, water heating, ventilation, lighting requirements.

IECC 2024: Duct insulation R-8 supply, R-6 return. Duct leakage ≤4 CFM25/100sf. Pipe insulation R-3 first 5ft. Ventilation per ASHRAE 62.2. Equipment per Manual J/S. 90% high-efficacy lighting (LED).

TAGS

IECC HVAC duct-sealing energy-code

DETAILS

code year

2024

code system

IECC

code section

R403

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